Nitrogen application in drought conditions

To answer the question, Yes, but choosing the right nitrogen source is more important in drought conditions; Urea is a bad choice at this time because it is water dependent. Moisture is required to convert urea into ammonium and if there is no appreciable rain then this process can be very slow resulting in high rates of ammonia volatilisation which could mean up to half of the nitrogen applied is lost to the atmosphere. Ammonium nitrate (AN) based nitrogen sources are stable during dry conditions with very low losses to volatilisation. Because AN contains nitrate, the grass plant has a readily available source of nitrogen which can be taken up by the plant through mass flow which does not pose any extra energy demands on the plant. Heavy dews are generally sufficient for the nitrogen in AN based products to diffuse into the soil. 

It’s important not to skip nitrogen applications after grazing even though growth may have slowed down to below 30 kg/ha/day, the plant still requires nitrogen and when rain does arrive there needs to be sufficient N to meet the sudden increase in daily growth rates which can jump by up to 50 kg/ha/day. Rain after a dry period when grass supply is tight usually sets the grazing platform up to produce excellent quality grass, high in ME and protein which will boost milk solids. Don’t be tempted to miss a round of N during a dry spell or you won’t reap the rewards when the rain does come! 

Check the daily grass growth rates in your area using our grass growth map.